Dry gasholder having a ballast actuated piston



July 3, 1951 F. K, VAN rr s 2,559,137

DRY GASHOLDER HAVING A BALLAST ACTUATED PISTON Filed March 20, 1947 INVENTOR fiedeflK/Kfl/a/z ffe/wll ATTORNEYS Patented July 3, 1951 UNITED STATES PATENT OFFICE DRY GASHOLDER HAVING A BALLAST ACTUATED PISTON Application March 20, 1947, Serial No. 735,900 In the Netherlands December 11, 1946 9 Claims.

The invention relates to a dry gasholder having a ballast actuated piston.

Various constructions of dry gasholders having pistons are already known. In order to obtain the required gas pressure the piston of these known gasholders is provided with ballast means which is disposed on the surface of the piston. By the fact that the centre of gravity of the piston and the ballast lies high, the danger presents itself that the tendency of the piston to take an inclined position is increased. Namely, when the piston in the gasholder, which can never be constructed with an absolutely circular cross section, gets caught in its downward movement, the piston will take an inclined position. Hereby the couple which is formed by the pressure of the wall of the gasholder on the piston and by the component of the force of gravity parallel to the upper surface of the piston will try to turn the piston further, so that it will take an even more inclined position.

This disadvantage is avoided by the gasholder according to this invention due to the fact that the centre of gravity of the ballast means is disposed below the piston such that the ballast acts to maintain the piston in its horizontal position. The couple which is then formed by the pressure of the wall of the gasholder on the piston and the component of the force of gravity parallel to the upper surface of the piston, hereby counteracts the turning of the piston by the factthat the centre of gravity is located below the surface of the piston. As the centre of gravity of the piston is displaced by lowering the ballast means, this couple increases.

By displacing the centre of gravity of the piston with ballast means to the upper surface of the piston, according to the invention the piston may be provided merely along its outer edge with guides, preferably rollers, co-operating with the inner wall of the gasholder. Therefore it is not necessary to provide a central guide, which protrudes considerably above the upper surface of the gasholder when the latter is filled, or which is constructed as a central column within the gasholder and along which guides run. In this latter structure an opening for the central column must be provided in the piston, which opening must be provided with sealing means.

A preferred embodiment of the gasholder according to this invention is characterized in that the piston is funnel-shaped, which funnel has in its centre a downwardly projecting portion, in which the ballast means is placed. In this embodiment the centre of gravity of the piston and ballast means will lie very low.

According to the invention the piston is preferably constructed as a shell, being therefore very readily deformable, as will be known from the theory of shell-construction, so that it does not offer appreciable resistance against moderate deformations.

In order to prevent the ballast means decreasing the flexibility of the shell to deformation, according to the invention ballast means is provided such that the shell-shaped piston maintains its freedom of deformation as much as possible. This may be effected in various ways. The ballast means may be suspended for example from the piston by securing to the centre of the piston a depending container the diameter of which is as small as possible at the point where it is secured to the piston. This container may be filled with ballast, for example, concrete. It is also possible to secure a cylindrical protruding portion, which is also constructed as a shell, on and integral with the lower face of the piston, at its centre, in which the ballast is spaced from the inside of the cylindrical wall of this protruding portion. Thereby the Wall of this cylinder keeps its deformability, so that the deformability of the piston constructed as a shell is only slightly decreased. The piston maintains an even greater freedom, if the ballast bears on the bottom of the cylindrical projection with a three point support, or if the ballast is suspended with a three point support from the piston or the cylindrical projection.

It is clear that various ways may be employed for suspending the ballast from the piston according to the properties it is desired to imp-art to the piston.

The invention is explained more fully below with reference to the accompanying drawing, in which:

Fig. 1 is a top elevational view of the gasholder according to my invention.

Fig. 2 is a transverse sectional view taken on the line 2-2 of Fig. 1. l

The gasholder l represented in the drawing has a circular cross section in which a funnel shaped piston 2 constructed as a shell, moves up and down. On its outer periphery this piston 2 is provided with a sealing strip 3 of synthetic rubber or other suitable material. Because this sealing strip protrudes downwards into the space of the gasholder the pressure of the gas in the gasholder produces a satisfactory seal between the wall of the gasholder and the piston.

On the outer periphery of the piston a number of guide-rollers 4 are provided to guide the piston within the gasholder.

The funnel-shaped piston 2 is provided at its centre with an opening which is closed by a downwardly protruding cylinder 5. In this cylin der, which also has a shell structure, ballast 6 is disposed spaced from the wall of the cylinder. The ballast is shown as bearing on the bottom of the cylinder with its weight distributed over the whole area of contact, but it is clear thatit may also bear on a few points only, for example on three points.

It will be understood that in the above only one embodiment of the gasholder is described, and

that it may be varied in several ways without departing from the'scope or the invention.

I claim:

1. A dry gasholder consisting of a container and a piston movable in said container, said piston being constructed as an inverted flexible conical shell and having a lateral surface, means establishing contact between said piston and said container all of said means lying contiguous to the perimeter of said lateral surface of said conical piston andsaid means including a sealing sliding along the inner wall of said container, said piston having a weight located substantially at the apex of said conical shell, the center of gravity of said weight being disposed in such a way that said weight actsto maintainthe piston in substantially horizontal position while permitting limited tilting.

2. A dry gasholder consisting of a container and a piston movable in said container, said piston being constructed as an inverted flexible 1 conical shell-like funnel and having a lateral surface, means establishing contact between said funnel and said containerall of said means l'ying contiguous to the perimeter of said lateral surface of said conical funnel andsaid means ineluding a sealing sliding along the inner wall-of said container, said funnel com-prising in its center a downwardly protruding portion containing a weight located substantially at the apex of saidconical funnel.

3. A dry gasholder consisting of a container and a piston movable in said container, said piston being constructed as an inverted flexible conical shell having a lateral surface and having a weight located substantially at the apex of saidb'onical piston, means-establishing contact between said conical piston and said container all of said means lying contiguous to the perimeter of the lateral surface of said conical piston and said means including a sliding seal, the center of gravity of said weight being disposed below the lateral surface of said conical pistonso that said weight acts to urge the piston toward the horizontal position and being disposed in such manner that the piston retains substantial 'deformability due to its flexible shell construction.

4. A dry gasholder consisting of a container and a piston movable in said container, said piston being'constructed as an inverted flexible conical shell-like funnel and having a lateral surface, means establishing contact between said conical funnel and said container all of said means lying contiguous to the perimeter of said lateral surface of said conical funnel and said means including a sliding seal, said funnel comprising in its center a downwardly protruding portion provided with a weight located substantially at the apex of said conical funnel, said weight being disposed in such a way in respect to said funnel that the funnel retains substantialdeformability due to its flexible shell construction.

5. A dry gasholder consisting of a container and a piston movable in said container, said piston being constructed as an inverted conical flexible shell having a lateral surface and having a weight located substantially at the apex of said conical piston, means establishing contact between said piston and said container all of said means lying contiguous to the perimeter of said lateral surfaceof said piston and said means including a sealing sliding along the inner wall of said container, the center of gravity of said weight being disposed in such a way that said weight acts to maintain the piston in substantially horizontal position while permitting tilting within the deformable limits of said lateral surface.

6. A dry gasholder consisting of a container and a piston movablein said container, said piston being constructed as an inverted conical flexible shell having a lateral-surface and having a weight located substantially at the apex of said conical piston, means establishing contact between said piston and said container all of said means lying contiguous to the perimeter of said lateral surfaceof said'piston and'said means including a sealing sliding along the inner wall of said container, the center of gravity of said weight being disposed-below said lateral surface so that said weight acts to urge the piston toward the horizontal position, the weight being disposed in sucha way in respect to the piston that the piston retains substantial deformability at the perimeter of said lateral surface due to said flexible shell construction.

'7. A dry gasholder comprising a substantially cylindrical container for gas, an invertedsubstantially conical flexible shell piston having a lateralsurface and disposed for movement with in said container, the lateral surface of said piston moving in inclined tiltable and deform able relation to the vertical wall of said cylin= der, means establishing contact between said piston and said container, all of saidmeans lying contiguous to said lateral surface of-sa-id piston and said means including a sliding seal-, and a weight disposed below said lateral surface of said piston preventing the inclination of said piston beyond sealing relation between said sliding seal and the wall of said container.

'8; A dry gasholder comprising -a substantially cylindrical vertically-arranged container and a piston movable vertically-in said. container, said piston being constructed as a deformable conical shell having a lateral surface, the lateral surface of said conical shell establishing a peripheral edge portion and saidedge portion-onlyengaging the inner wall of said container for movement in sealing contact along the inner wall of said container, and a weight carried by said conical piston and arranged centrally or and be-e low said edge port-ion substantially at the apex of said conical piston to' urge the base ofsaid piston toward the honizontal-tposition'.

9. A dry asholder as set out in claim 8 in 5 which the peripheral edge portion is provided with a plurality of guide-rol1ers contacting the wall of said container to guide the piston within said container.

FREDERIK KAREL THEODOOR VAN ITERSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Wiggins July 13, 1926 Number Number Number 

